I. Field of the Invention
This invention relates generally to pump apparatus for pumping fluids at relatively high pressures, and more particularly to the improved design of a pump whereby the construction thereof is greatly simplified and the overall size is significantly reduced when compared to prior art pumps having corresponding capacities.
II. Discussion of the Prior Art
Heretofore it has been the practice in the fluid handling arts to design pump structures so as to include a piston or plunger assembly which is secured to the end of a piston rod which, in turn, is joined to a crosshead. The crosshead is then mechanically linked to the crankshaft through a connecting rod which conventionally includes a sleeve bearing or bushing and a crosshead pin for joining the end of the connecting rod to the crosshead. The other end of the connecting rod has a generally semicircular yoke so as to receive a circular lobe on a crankshaft and a second semicircular clamp member must be bolted in place to firmly hold the connecting rod to the crankshaft. It is also a common practice to include a shell-type bearing which may be babbitt-lined between the mating parts of the connecting rod and the crank surface with which it cooperates. The combination of the connecting rod and the crosshead converts the rotary motion of the shaft to reciprocatory motion of the piston or plunger. This conventional construction includes a comparatively large number of parts and, further, tends to unduly increase the overall length of the pump structure.
Furthermore, it has been common practice in the past to specifically design individual pumps to meet desired performance goals in terms of pressures and flow rates. This necessarily creates problems for a manufacturer in that he is unable to take advantage of economies of scale. It would therefore appear advantageous if a pump mechanism could be designed so that by merely providing an adapter sleeve in the cylinder block, the same cylinder block, crankcase assembly, plunger push rods, seals, guides and other items may be used in pump structures designed to meet a variety of operating parameters.
Typical of the prior art over which the present invention is deemed to be a significant improvement is the Model 820 pump manufactured and sold by Cat Pumps Corporation of Minneapolis, Minn. and the Model 420 Triplex pump manufactured and sold by the John Beam Division of the FMC Corporation of Lansing, Mich. The reader is referred to the Data Sheets of those companies for a more detailed description of the prior art against which the present invention is to be compared.